Variable stroke mechanism



Filed Oct. 26, 1934 V 5 Sheets-Sheet l Feb. 15, 1938. A. J; HARRISVARIABLE STROKE MECHANISM s Shets-Sheet 2 Filed Oct. 26, 1934 pumpscovered by Patents Numbers 1,858,184 and Patented Feb. 15, 1938.

UNITED STATES PATENT OFFICE VARIABLE STROKE MECHANISM tion of IllinoisApplication October 26, 1934, Serial No. 750,057

2 Claims.

My invention relates to pumps and particularly to chemical pumps havingcapacity adjustment to permit supplying diiferent proportionate amountsof liquid chemicals.

The invention. relates in some aspects to liquid 1,858,185, issued May10, 1932, to C. O. Buenger of Chicago, Illinois.

One of the objects of the present invention is to provide a simple,practical and advantageous construction of pump of the class specified.

Another object of the invention is to provide improved and advantageousmeans for securing adjustment of the capacity of the pump.

Another object of the invention is to secure this adjustment withoutunfavorably affecting the stroke of the piston.

Other objects of the invention will appear and be pointed outhereinafter.

In the accompanying drawings:

Fig. 1 is a side elevation of a pump embodying my present invention;

Fig. 2 is a plan view of the same;

Fig. 3 is a vertical elevation taken on the line 34 in Fig. 1; I

Fig. 4 is a horizontal section taken on the line 4-4 in Fig. 1;

Fig. 5 is a vertical-section of the lower end of the pump cylinder; and

Fig. 6 is a transverse section taken on the line 6--6 in Fig. 5.

In the accompanying drawings, I show a pump I embodying a base on whichmay be mounted an electric motor 2 connected by a rotary shaft '8 to aspeed reducing device 4.

'The speed reducing device 4 is'preferably pro vided with a rotary crankarm 5 whose outer end is pivotally connected at 5 to one end of a-link6, the other end of link 6 being pivotally connected at l to a swingingyoke 8 which is pivotally connected at its opposite end by pivots 9 toswinging arms i8 which are in turn pivotally connected at ii to theupper end of the pump case l2, which latter is secured by bolts H to abase IE on the main base or platform I.

The yoke 81s pivotally connected with the reciprocating piston orplunger i8 which is arrangedto reciprocate in the piston cylinder orbarrel I! on the case I2, being preferably formed integrally and as apart of said case l2. The rotation of crank arm 5, resulting in theactuation of link 8 and swinging of yoke 8 about its fulcrum pivots 9,results in the reciprocation of plunger l6 and thereby effects thepumping act.

This yoke 8 is preferably arranged for longitudinal adjustment so thatits point of pivotal connection with-piston I6 may be varied, them bychanging its stroke and thereby causing a variation in the length of thepiston stroke to 'accomplish the desired variation in the amount of 5liquid pumped to secure desired proportions in a chemical mixture or thelike. This longitudinal shifting of the yoke 8 and consequent change ofpoint of pivotal connection of said yoke with reciprocating plunger I 6,has certain definite ad- 10 vantages which will be pointed out later on.

While the longitudinal shifting of this yoke 8 and consequent variationin the point of pivotal connection'with the reciprocating plunger couldbe accomplished in various ways, I show herein one construction which Ihave found very advantageous and satisfactory.

In this construction the yoke 8 is preferably formed of two side membersli -8, which are arranged on opposite sides of the pump plunger l6, andthese side members 8 are made in the form of guides to support and guidea carriage l8 which is preferably made in U form, as shown in Fig. 4,and fitted between the side members 8* -8 and provided with longitudinalside slots to receive said side members 8, as shown in Fig. 3, wherebythe yoke 8 may be shifted along carriage l8 by sliding on the members8*. The sides of the carriage I8 are arranged on opposite sides ofpiston l 6, as shown in Fig. 4, and provided with screws I9 which serveas pivotal pins for pivotally connecting carriage l8 with piston iii.For shifting yoke'8, a rotary member 2| is provided and arranged forrotation in a bearing 22 in carriage l8 but will be held againstlongitudinal movement by ring 23 fitting in a recess in the end of rod2| and in a co-operating recess in carriage l8.

This rod 2i extends lengthwise of yoke 8 and out through an end member24 thereon, being provided with a handwheel 25 at its outer end. Saidrod 2| is screw-threaded and co-operates with the threads oncross-member 24, as shown in Fig. 4, whereby rotation of handwheel 25will cause rotation of rod 2i and adjustment of said rod relatively toyoke 8 by meansof threads on said rod 2| and member 24, and therebycause the shifting of yoke 8 longitudinally along yoke bars 8' and theconsequent change in the point of pivotal connection of yoke 8 with thepiston rod or plunger i8. I

Thus it will be seen that this longitudinal adjustment of yoke 8, withits effect of changing the point of pivotal connection between said yokeand reciprocating plunger It, has the eifect of 55 changing the point ofapplication of power of the lever which is in efiect formed by yoke- 8,and shortening or lengthening the length of leverarm or part of thelever which acts upon plunger I6 and thereby varies the length of strokeof said plunger 5. As handwheel is turned to shift yoke ,8 to the right,(Fig. 1) the distance between pivots l9 and 9 is decreased, andconsequently the effective length of lever formed by yoke 8 is shortenedand the plunger IE will have a shorter stroke. Likewise, a converseshifting of yoke 8 to the left, (Fig. 1) will have the efiect ofincreasing the distance between pi'vot pins 9 and i9, therebylengthening the effective lever arm operating on the piston l6 andlengthening the stroke of said piston.

A marked advantage of this arrangement is that while the stroke of thepiston is thus varied as desired to secure changes in the piston strokeand consequent changes in the pump output, the

stroke or location of the piston or plunger is not unfavorabiy affected,as has been the case in other constructions for securing variation inthe plunger stroke. This is due to the fact that shifting of yoke 8 toone side or the other retains the point ofpivotal connection betweenyoke 8 and plunger 16 at substantially the same height -or elevation andso does not have the effect of varying the position of the piston, inthe cylinder, by bodily raising or lowering it and causing it to work ina different position in the piston chamber, as is the case with certainother constructions and arrangements for securing variation of pistontravel. This present arrangement on the other hand has the effect ofmaintaining the piston plunger in a substantially constant position,changing only the length of stroke, notwithstanding shifting in thepoint of connection of piston with the yoke 8, and hence the piston willWork in the lower portion of the piston cylinder where it is originallyplaced by adjustmentv of the parts, notwithstanding changes in thelength of stroke of the'piston.

Referring to Figs. 5 and 6, there is shown in those figures anarrangement for packing and cleansing the piston in the piston cylinder,so as to prevent the formation of solid material from -the chemicalsolutions which would interfere with the proper operation of the pump.

These figures show the piston rod it with its lower enlarged end l6 andthe upper end of the piston cylinder or chamber I1, and a stufling boxarrangement for the same. This stuffing box arrangement involves apacking gland 21 adapted to fit in the upper end of cylinder I1, andpacking material 28-28 arranged in the packing chamber, and a ring 29also arranged in said chamber and surrounding the piston end 16 anddividing the packing material 28 into two parts. This ring 29 hasapertures 30 which are arranged opposite apertures 3| formed in thecylinder end I1, so that an inlet pipe for the liquid may be connectedto one aperture 3! and an outlet pipe for the same to the other aperture3!, thereby permitting circulation of water or other liquid, if desired,through the packing gland to prevent freezing or coagulation of thechemical mixture being pumped, and for other purposes if desired.

It wil be understood that changes and modifications may be made withoutdeparting from the spirit of the invention.

What I claim is:

1. Actuating means for a pump piston, comprising a power member having arotarycrank arm, a link having one end pivotally connected with saidcrank arm, a piston-actuating lever pivotally connected withthe otherend of said link, said piston-actuating lever being in the form of ayoke extending crosswise of the piston and having members on oppositesides of the piston, a carriage along which the side members of saidyoke are slidable and provided with pivot pins forming a pivotalconnection with the piston, swinging supporting links pivoted at one endto the end of said yoke opposite said link and pivoted at the other endto the piston casing, and means for adjusting said piston connectingcarriage lengthwise of said yoke, said means comprising a rotarythreaded bar or rod having one end connected with said carriage so as topermit rotary but prevent longitudinal movement, said threaded barengaging a threaded member on the yoke, and a rotary handle on said barrod to turn the same and thereby cause said threaded'bar rod to adjustsaid carriage.

2. Actuating means for a piston. comprising a power member having arotary crank arm, a link having one end pivotally connected to saidcrank arm, a piston-actuating lever pivotally connected with the otherend of said link, said piston-actuating lever comprising a pair ofspaced parallel bars forming a pair of tracks, aU-shamd carriageembracing and pivotally connected to the piston and embraced by saidbars and engaging said tracks, means for advancing said lever withrespect to said carriage comprising a screw member engaging the bightportion of the U-shaped carriage and rotatable but immovablelongitudinally with respect thereto, a transverse bar joining the twoparallelbars, said screw being threaded through said transverse bar sothat upon turning of the screw the parallel bars are moved with respectto the carriage, and a swinging fulcrum for the piston-actuating lever.

ALBERT J. HARRIS.

